One of the packages of the above-described type on the market is provided with a cutting element which by means of a pressure applied thereto inserts into the liquid container, which is closed off by a thin membrane; the cutting element ruptures the membrane so that the powders can penetrate into the container. A package of this type is described, for example, in Italian patent for industrial invention no. 1,066,140, wherein the cutting element is in fact a hollow cylinder with an oblique-section end, made in a single piece with walls which close the mouth of the container. This package exhibits a lateral strip, removable by tugging along two easy-break parallel lines exhibiting a tab-pull; the user can grip this stip, the removal of which enables the cutting element to make an axial movement. When it is desired to mix the powder with the liquid solvent, the strip must first be removed and then the cutting element pressed using a finger so that the bottom of the little powder container is ruptured and the powders can mix with the liquid.
Another prior-art package comprises a protection hood, which covers the cutting element and the powder container and which is destined to be removed by tearing at the moment of use in order that the cutting element can be pressed. A package of this type is shown, for example, in Italian application for industrial invention no. RM91A000831.
The prior art comprises U.S. Pat. No. 4,982,875 which discloses a package comprising a capsule inserted internally of the upper mouth of the container. The capsule is superiorly open and is separated from the inside of the container. The capsule has a breakable bottom. A rupturing of the bottom setting the capsule in communication with the inside of the container. A cutting element is inserted internally of the capsule. The cutting element has a bottom end destined in use to break the bottom of the capsule. A cap is arranged on the container in such a way as to cover the capsule and the cutting element. The cap exhibits a thread with which a screw-coupling is achieved, by means of which coupling the cap can move axially downwards with respect to the container. The axial downward movement causes the cap to interact with the cutting element in order to rupture the bottom of the capsule.
The prior-art packages contain some drawbacks.
Firstly, in order to avoid a deterioration of the powder quality, the coupling between the external surface of the cutting element and the internal surface of the powder container must be sealed to guarantee a hermetic seal on the container. However, the correct realisation of such coupling is especially difficult to achieve, inasmuch as if the coupling is too tight, a strong pressure will have to be applied to the cutting element, which is not only hard to do but can cause the user to perform the operation wrongly, i.e. not by pressing with a finger on the cap-capsule but by tipping up the package and pressing the cap against a solid surface. This can mean that the mixture is not obtained in the correct manner, as the powder does not fall directly into the liquid but vice-versa, leading to the formation of lumps which are difficult to remove from the cap-capsule. Thus a wrong mixture of the medicine is obtained.
In series production of plastic objects at industrial levels it is quite difficult to obtain size tolerances which would guarantee a constantly correct and desired connection between the cutting element and the cap-capsule.
A further problem in prior-art packages is as follows: at the moment of use, after the mixing phase of the substances (powders and liquid), the container is opened to allow the mixture to be removed. The powder container, which stays in the mouth of the container even after the cap has been extracted, represents an obstacle which can disturb the pouring-put of the mixture, making it irregular and discontinuous.